Beyond the limit; Invisible Mountain;; Discrimination series -P.30

However, the situation is totally different for the Rounds.
If each human race was equal, all of their acts including their conquering the world,
slavering the Triangles and their isolation policies would lose the fair grounds.
It means that hey became evil, which they would never be able to accept.

Nousos have finally gone beyond the limit. The Rounds realized that they could not stand it anymore,
so they have united and firmly vowed that "We will attack, conquer, destroy Nouso to prove them as an inferior race."